Abstract:

A replacement light fixture for directing light emitted from a light
source toward an area to be illuminated, including a base member upon
with the light source is positioned and a reflector assembly detachably
secured to a first and second mounting brackets that are mounted to a
portion of the preexisting light fixture housing such that a lens portion
of the reflector assembly overlies the light source and such that
substantially all of the light emitted from the light source passes
through the lens portion

Claims:

1. A bracket assembly for use with a light fixture housing, the housing
having a pair of spaced and opposed end walls with a pair of spaced and
opposed side walls extending therebetween, the bracket assembly
comprising: a first mounting bracket and a second mounting bracket, each
mounting bracket being sized and shaped to be mounted on one of the
respective ends of the light fixture housing, and an elongate reflector
coupled to the mounting brackets and extending therebetween.

2. The bracket assembly of claim 1, each mounting bracket being sized and
shaped to be substantially received within the housing.

3. The bracket assembly of claim 2, each mounting bracket being sized and
shaped to be self-centering on the respective end walls of the light
fixture housing.

4. The bracket assembly of claim 1, each mounting bracket being sized and
shaped to be self-centering on the respective end walls of the light
fixture housing.

5. The bracket assembly of claim 1, each mounting bracket being sized and
shaped to be self-centering on the housing end walls with respect to the
side walls of the light fixture housing.

6. The bracket assembly of claim 1, the reflector being sized and shaped
to be selectively coupled to the respective mounting brackets.

7. The bracket assembly of claim 1, further comprising a powered light
source disposed within the housing for emitting light, the reflector
being sized and shaped to shape the distribution of light emitted from
the light fixture.

8. The bracket assembly of claim 1, further comprising a powered light
source disposed within the housing for emitting light, the reflector
being sized and shaped to reduce high angle glare of the light emitted
from the light source.

9. The bracket assembly of claim 1, further comprising a powered light
source disposed within the housing for emitting light, the reflector
being sized and shaped to visibly obfuscate the light source at a high
angle degree of incidence with respect to the light fixture housing.

10. A retrofit assembly for use with a light fixture housing, the housing
having a pair of spaced and opposed end walls with a pair of spaced and
opposed side walls extending between the end walls, the retrofit assembly
comprising: a first mounting bracket and a second mounting bracket, each
mounting bracket being sized and shaped to be substantially received
within the housing and mounted on one of the respective ends of the light
fixture housing and to be self-centering on such end wall, and an
elongate reflector extending between and mounted to the mounting
brackets.

11. The retrofit assembly of claim 10, further comprising a powered light
source disposed within the housing for emitting light, the reflector
being sized and shaped to shape the distribution of light emitted from
the light fixture.

12. The retrofit assembly of claim 10, further comprising a powered light
source disposed within the housing for emitting light, the reflector
being sized and shaped to reduce high angle glare of the light emitted
from the light source.

13. The retrofit assembly of claim 10, further comprising a base member
having at least one elongate base member with a first end and a spaced
second end, the ends of the base member being sized and shaped to be
coupled to the mounting brackets.

14. The retrofit assembly of claim 13, further comprising at least one
lamp socket mounted on the base member.

15. The retrofit assembly of claim 14, further comprising at least one
lamp received within the at least one socket.

16. The retrofit assembly of claim 14, the at least one lamp socket
comprising at least one pair of spaced lamp sockets sized and shaped to
receive a liner light source extending therebetween.

17. The retrofit assembly of claim 16, the at least one lamp being powered
and emitting light, the reflector being sized and shaped to reduce high
angle glare of the light emitted from the at least one lamp.

18. A retrofit assembly for a recessed light fixture housing mounted in a
ceiling plane, the light fixture housing having opposed end walls, each
end wall having a bottom edge portion that lies within the ceiling plane,
comprising:a. a longitudinally extending base member;b. a first mounting
bracket and an opposed second mounting bracket, each mounting bracket
being substantially self-centering and selectively mountable to the
respective end walls of the preexisting recessed light fixture housing;c.
a means for connecting the base member to the mounting brackets; andd. a
longitudinally extending reflector detachably secured to the first and
the second mounting brackets.

19. The retrofit assembly of claim 18, wherein the mounting brackets are
received on the bottom edge portion of the housing end walls.

20. A retrofit light fixture for use with a recessed light fixture housing
having opposed end walls, each end wall having a bottom edge portion that
is positioned within a ceiling plane, comprising:a first mounting bracket
and an opposed second mounting bracket, each mounting bracket having a
lower portion defining a channel that is selectively mountable to the
bottom edge portion of a respective end wall of the housing such that a
bottom surface of the channel is positioned substantially within the
ceiling plane, each mounting bracket also being sized and shaped to be
self-centering on the respective end walls of the light fixture housinga
base assembly comprising a longitudinally extending base member having a
proximal edge and an opposed distal edge, the base assembly having a
first installation position in which the base member is suspended from
the first mounting bracket and a second operating position in which the
base member is selectively secured to the second mounting bracket; anda
longitudinally extending reflector assembly selectively secured to the
first and second mounting brackets.

Description:

[0001]This application is a continuation of U.S. Utility patent
application Ser. No. 11/706,467, filed on Sep. 13, 2007, now U.S. Pat.
No. 7,635,198, issued Dec. 22, 2009, which claims priority to U.S.
Provisional Application Nos. 60/722,231, filed on Feb. 10, 2006, and
60/860,671, filed on Nov. 22, 2006, and is a continuation-in-part of U.S.
Utility patent application Ser. No. 10/970,615, filed on Oct. 21, 2004,
now U.S. Pat. No. 7,229,192, issued Jun. 12, 2007, and U.S. Utility
patent application Ser. No. 10/970,625, filed on Oct. 21, 2004, now U.S.
Pat. No. 7,261,435, issued Aug. 28, 2007, which claims priority to U.S.
Provisional Application No. 60/580,996, filed on Jun. 18, 2004, all of
which are incorporated in their entirety in this document by reference.

FIELD OF THE INVENTION

[0002]The present invention generally relates to light fixtures for
illuminating architectural spaces. The invention has particular
application in light fixtures using fluorescent lamps, such as the T5
linear fluorescent lamp, as the light source. More particularly, the
invention relates to a replacement light fixture and a method of
retrofitting preexisting recessed light fixtures.

BACKGROUND ART

[0003]Numerous light fixtures for architectural lighting applications are
known. In the case of fixtures that provide direct lighting, the source
of illumination may be visible in its entirety through an output aperture
of the light fixture or shielded by elements such as parabolic baffles or
lenses. A light fixture presently used in a typical office environment
comprises a troffer with at least one fluorescent lamp and a lens having
prismatic elements for distributing the light. Also known are light
fixtures that use parabolic reflectors to provide a desired light
distribution. The choice of light fixture will depend on the objectives
of the lighting designer for a particular application and the economic
resources available. To meet his or her design objectives, the lighting
designer, when choosing a light fixture, will normally consider a variety
of factors including aesthetic appearance, desired light distribution
characteristics, efficiency, lumen package, maintenance and sources of
brightness that can detract from visual comfort and productivity.

[0004]An important factor in the design of light fixtures for a particular
application is the light source. The fluorescent lamp has long been the
light source of choice among lighting designers in many commercial
applications, particularly for indoor office lighting. For many years the
most common fluorescent lamps for use in indoor lighting have been the
linear T8 (1 inch diameter) and the T12 (1.5 inch diameter). More
recently, however, smaller diameter fluorescent lamps have become
available, which provide a high lumen output from a comparatively small
lamp envelope. An example is the linear T5 (5/8 inch diameter) lamp
manufactured by Osram/Sylvania and others. The T5 has a number of
advantages over the T8 and T12, including the design of light fixtures
that provide a high lumen output with fewer lamps, which reduces lamp
disposal requirements and has the potential for reducing overall costs.
The smaller-diameter T5 lamps also permit the design of smaller light
fixtures. The newer technology lamps allow for the design of light
fixtures that produce equivalent illumination with only a fraction of the
number of lamps that would have been used in a conventional light fixture
using older technology lamps.

[0005]Some conventional fluorescent lamps, however, have the significant
drawback in that the lamp surface is bright when compared to a lamp of
larger diameter. For example, a conventional T5 lamp can have a surface
brightness in the range of 5,000 to 8,000 footlamberts (FL), whereas the
surface brightness of the larger T8 and T12 lamps generally is about
3,000 FL and 2,000 FL, respectively (although there are some versions of
linear T8 and T12 lamps with higher brightness). The consequence of such
bright surfaces is quite severe in applications where the lamps may be
viewed directly. Without adequate shielding, fixtures employing such
lamps are very uncomfortable and produce direct and reflected glare that
impairs the comfort of the lighting environment. Heretofore, opaque
shielding has been devised to cover or substantially surround a
fluorescent lamp to mitigate problems associated with light sources of
high surface brightness; however, such shielding defeats the advantages
of a fluorescent lamp in regions of distribution where the lamp's
surfaces are not directly viewed or do not set up reflected glare
patterns. Thus, with conventional shielding designs, the distribution
efficiencies and high lumen output advantages of the fluorescent lamp can
be substantially lost.

[0006]A further disadvantage to traditional parabolic and prismatic
troffers is the presence of distracting dynamic changes in brightness
level and pattern as seen by a moving observer in the architectural
space. Additionally, traditional parabolic and prismatic troffers allow
direct or only slightly obscured views of the lamp source(s)) at certain
viewing angles (low angles for both the parabolic and prismatic and most
transverse angle for prismatic). This unaesthetic condition is remedied
by indirect and direct-indirect fixture designs, but typically with a
significant loss of efficiency.

[0007]Another known solution to the problem of direct glare associated
with the use of high brightness fluorescent lamps is the use of biax
lamps in direct-indirect light fixtures. This approach uses high
brightness lamps only for the uplight component of the light fixture
while using T8 lamps with less bright surfaces for the light fixtures
down-light component. However, such design approaches have the drawback
that the extra lamps impair the designer's ability to achieve a desired
light distribution from a given physical envelope and impose added
burdens on lamp maintenance providers who must stock and handle two
different types of lamps.

[0008]Conventional parabolic light fixture designs have several negative
features. One of these is reduced lighting efficiency. Another is the
so-called "cave effect," where the upper portions of walls in the
illuminated area are dark. In addition, the light distribution of these
fixtures often creates a defined line on the walls between the higher lit
and less lit areas. This creates the perception of a ceiling that is
lower than it actually is. Further, when viewed directly at high viewing
angles, a conventional parabolic fixture can appear very dim or, even,
off.

[0009]The present invention overcomes the above-described disadvantages of
light fixtures using brighter light sources by providing a configuration
that appears to a viewer as though it has a source of lower brightness,
but which otherwise permits the light fixture to advantageously and
efficiently distribute light generated by the selected lamp, such as the
exemplified T5 lamp. The light fixture of the present invention reduces
distracting direct glare associated with high brightness light sources
used in direct or direct-indirect light fixtures. This reduction in glare
is accomplished without the addition of lamps and the added costs
associated therewith.

[0010]As discussed above, recent developments in lamp technologies have
resulted in higher efficiency, brighter lamps with better color
rendering. Particularly, these developments have resulted in the
availability of new technology lamps and light fixtures with the
performance describe above. Commercial clients desire the ability to more
efficiently and effectively illuminate their work or display environments
by utilizing the newer technology lamps and light fixtures. However, the
newer technology lamps cannot be installed into existing fixtures as they
require different lamp holders and ballasts.

[0011]Replacement of existing fixtures is very costly. This option
requires the purchase of completely new fixtures, wiring and construction
costs of removing the old fixtures and installing the new fixtures, as
well as the additional burden of the inconvenience and cost of closing
down sections of the commercial structure as the construction proceeds.

[0012]The present invention particularly addresses the cost and
convenience issued involved with newer technology lamps, sockets, and
ballasts. The present invention also allows installation of a newer
technology light fixture without disturbing the ceiling or the plenum
area above the ceiling, which eliminates potential environmental
concerns, such as asbestos contamination and the cost of asbestos
removal, that can be associated with disturbing the ceiling or plenum.

SUMMARY OF THE INVENTION

[0013]The present invention relates to a replacement or retrofit light
fixture, or troffer, for efficiently distributing light emitted by a
light source into an area to be illuminated. The lens and reflector of
the present invention increase the light efficiency of the replacement or
retrofit light fixture and diffuses the light relatively uniformly, which
minimizes the "cave effect" commonly noted in areas using conventional
parabolic light fixtures in the ceiling.

[0014]In one embodiment, suitable for retrofit or replacement
applications, the present invention relates to a downlight light fixture
for efficiently distributing light emitted by a light source into an area
to be illuminated that can be mounted in a preexisting light fixture
housing, which can be, in one aspect, conventionally mounted therein a
ceiling.

[0015]In one exemplary embodiment, the retrofit light fixture of the
present application can comprise a longitudinally extending base member
that is configured to mount therein a preexisting recessed light fixture
housing mounted in and above a ceiling plane. The retrofit light fixture
can also comprise a first mounting bracket and an opposed second mounting
bracket. In one aspect, each mounting bracket can be configured for
mounting to an edge portion of a respective end wall of the light fixture
housing. In a further aspect, the base member is hingeably connected to
the first mounting bracket such that the base member can be move about
and between an installation position, in which the base member is
suspended from the first mounting bracket, and an operating position, in
which the base member is selectively secured to the first and second
mounting brackets.

[0016]In a further aspect, the retrofit light fixture can further comprise
a longitudinally extending reflector assembly that comprises at least one
elongated lens. In one aspect, the reflector assembly is constructed and
arranged to be detachably secured to a lower portion of the first and
second mounting brackets such that the reflector assembly is positioned
at or above the ceiling plane of the ceiling and underlies the base
member of the base assembly. In this aspect, it is contemplated that the
reflector assembly and the lens can be, in one example, formed integral
to each other. In a further aspect, it is contemplated that the lens is
positioned with respect to a portions of the reflector assembly to
receive light emitted by the light source and distribute it such that
glare is further reduced. In a preferred embodiment, the lens of this
exemplary retrofit light fixture receives and distributes substantially
all of the light emitted by the light source.

[0017]In an additional aspect, the base member is configured to receive at
least one light source that is releasably mounted to electrical lamp
sockets, which are connected to portions of the base member. In one
example, a ballast is mounted to a top surface of the base member such
that the ballast is hidden from view of an external observer when the
base member is mounted to the preexisting housing. In one aspect, a
movable access door is provided that can be opened and closed by an
operator to access a ballast that is disposed in an interior cavity that
is formed between the top surface of the base housing and portions of the
preexisting housing. In another aspect, the ballast can be mounted to a
portion of the top surface of the movable access door for ready access to
the ballast by an operator.

[0018]Related methods of operation are also provided. Other systems,
methods, features, and advantages of the replacement or retrofit light
fixture for distributing generated light will be or become apparent to
one with skill in the art upon examination of the following figures and
detailed description. It is intended that all such additional systems,
methods, features, and advantages be included within this description, be
within the scope of the replacement or retrofit light fixture for
distributing generated light, and be protected by the accompanying
claims.

BRIEF DESCRIPTION OF THE FIGURES

[0019]The accompanying drawings, which are incorporated in and constitute
a part of this specification, illustrate certain aspects of the instant
invention and together with the description, serve to explain, without
limitation, the principles of the invention. Like reference characters
used therein indicate like parts throughout the several drawings.

[0020]FIG. 1 is perspective view of one embodiment of the retrofit light
fixture of the present invention mounted therein a preexisting light
fixture housing.

[0021]FIG. 2 is a cross sectional view of one embodiment of the retrofit
light fixture of the present invention, showing two exemplary
lens/reflector embodiments. On the left is shown an exemplary reflector
assembly comprises a vacuum formed reflector and a preformed lens that is
connected to a cut out center section of the vacuum formed reflector. On
the right is shown a reflector assembly having a lens that is integrally
formed with the reflector assembly via a conventional injection molding
process.

[0022]FIG. 3 is a cross sectional view of one embodiment of the retrofit
light fixture of the present invention mounted therein a preexisting
light fixture housing.

[0023]FIG. 4 is an enlarged sectional view of an exemplary embodiment of a
reflector assembly, showing corner detail of the reflector assembly
formed via an injection molding process.

[0024]FIG. 5 is an enlarged sectional view of an exemplary embodiment of a
reflector assembly, showing corner detail of the reflector assembly
formed via a vacuum forming process, and showing a secondary metal frame
that surrounds the peripheral edge of the reflector assembly.

[0025]FIGS. 6A-6C are elevational views of an exemplary embodiment of a
mounting bracket of the present invention.

[0026]FIG. 6D is a cross-sectional view of the mounting bracket of FIG. 6B
taken along line 6D-6D.

[0027]FIG. 7A is a bottom elevational view of an embodiment of a base
member of a base assembly of the retrofit light fixture of the present
invention.

[0028]FIG. 7B is a cross-sectional view of the base member of FIG. 7A
taken along line 7B-7B.

[0029]FIGS. 8A-8B are elevational views of an exemplary embodiment of a
hinge bias member that is configured to be coupled to an edge of a
reflector assembly of the present invention.

[0030]FIG. 9 is an enlarged partial perspective view of the end edge
detail of an exemplary reflector assembly, showing a latch and a spring
hinge bias member.

[0031]FIG. 10 is a partial perspective view of one embodiment of a
mounting bracket of the present invention coupled to an edge portion of
an end wall of the preexisting light fixture housing.

[0032]FIG. 11 is a partial perspective view of a base member of a base
assembly being hung from the male tab protrusions of the mounting
bracket, and showing the respective power leads connecting the lamp
sockets and the ballast, the power leads connecting the ballast and the
existing power leads of the preexisting light fixture and the respective
ground leads operatively coupled. A splice box is also shown coupled to
the surface of the preexisting light fixture housing.

[0033]FIG. 12 is a bottom perspective view of the base assembly rotated up
and mechanically connected to the mounting bracket that is positioned
opposite the hingedly connected mounting bracket.

[0034]FIG. 13 is a cross-sectional view of one embodiment of a reflector
housing of the reflector housing showing a pair of opposing angled end
faces.

[0035]FIG. 14 is a partial exploded view of one exemplary embodiment of
the reflector assembly showing two preformed lens being coupled to
respective center portions of the hollows of the reflector assembly.

[0036]FIG. 15 are cross sectional views of one embodiment of the retrofit
light fixture of the present invention, showing the reflector assembly
being inserted therein a preexisting light fixture without removing the
preexisting lamps and ballast. Similar to FIG. 2 above, two exemplary
lens/reflector embodiments on illustrated in the same figure for
illustration purposes. On the left is shown an exemplary reflector
assembly that can comprise a vacuum formed reflector and a preformed lens
that is connected to a cut out center section of the vacuum formed
reflector. On the right is shown a reflector assembly that has an
integrally formed lens, which is exemplarily formed via a conventional
injection molding process.

[0037]FIG. 16 is an exploded top perspective view of one embodiment of a
lens assembly of the light fixture of the present invention showing an
elongated lens and a diffuser inlay.

[0038]FIG. 17 is a cross-sectional view of the lens assembly of FIG. 16,
taken along line 17-17.

[0039]FIG. 18 is an enlarged partial cross-sectional view of a lens,
showing one embodiment of an array of prismatic elements disposed on a
surface of the lens.

[0040]FIG. 19 is an enlarged partial cross-sectional view of a lens,
showing an alternative embodiment of the array of prismatic elements.

[0041]FIGS. 20 and 21 are enlarged partial cross-sectional views of a
lens, showing still further alternative embodiments of the array of
prismatic elements.

[0042]FIG. 22 shows an enlarged partial cross-sectional view of one
embodiment of the lens of the present invention with a diffuser inlay in
registration with a portion of the prismatic surface of the lens.

[0043]FIG. 23 is a perspective view of a first embodiment of a replacement
light fixture configured to be selectively mounted to a preexisting light
fixture housing that is mounted therein the ceiling, showing an
integrated assembly of a base housing and reflector/lens that is
pivotally mounted to a portion of the preexisting light fixture housing
in an open, access position.

[0044]FIG. 24 is a perspective view of the replacement light fixture of
FIG. 23 is the closed, mounted position.

[0045]FIG. 25 is a cross-sectional view of the replacement light fixture
of FIG. 23, showing a ballast for the replacement light fixture mounted
to a portion of preexisting light fixture housing.

[0046]FIG. 26 is a perspective view of a second embodiment of a
replacement light fixture, showing a base housing of the replacement
light fixture being connected to a portion of a preexisting light fixture
housing, the base housing configured to releasably mount at least one
light source and a ballast operably connected to the at least one light
source.

[0047]FIG. 27 is a partial perspective view of the replacement light
fixture of FIG. 26, showing a lock member configured to mount to edge
portions of a pair of opposed reflector members to secure the reflector
members relative to the preexisting light fixture housing.

[0048]FIG. 28 is a perspective view of the replacement light fixture of
FIG. 27, showing the replacement light fixture mounted to the preexisting
light fixture housing in the ceiling.

[0049]FIG. 29 is a perspective view of a third embodiment of a replacement
light fixture of the present invention, showing the replacement light
fixture mounted to a preexisting light fixture housing in the ceiling.

[0050]FIG. 30 is a perspective view of the replacement light fixture,
showing a base housing of the light fixture being connected to a portion
of the preexisting light fixture housing, the base housing configured to
releasably mount at least one light source and a ballast operably
connected to the at least one light source.

[0051]FIG. 31 is a perspective view of the replacement light fixture of
FIG. 29, showing a selectively movable access door having a ballast
mounted to a top side of the access door.

[0052]FIG. 32 is a perspective view of the replacement light fixture of
FIG. 29, showing an integral reflector assembly being releasably
connected to the base housing of the replacement light fixture.

[0053]FIG. 33 is a perspective top view of the base housing of FIG. 32.

[0054]FIG. 34 is a perspective top view of the integral reflector assembly
of FIG. 29.

[0055]FIG. 35 is a perspective view of a fourth embodiment of a
replacement light fixture of the present invention, showing the light
fixture mounted to a preexisting housing in the ceiling.

[0056]FIG. 36 is a perspective view of a base housing of the replacement
light fixture, the base housing configured to releasably mount at least
one light source and a ballast operably connected to the at least one
light source, the base channel further showing a channel, with a
selectively removable channel cover, that is configured for mounting the
ballast of the light fixture.

[0057]FIG. 37 is a perspective view of the base housing of FIG. 36 being
mounted to the preexisting light fixture housing.

[0058]FIG. 38 is a perspective view of the base housing of FIG. 37,
showing the channel cover removed and the ballast of the fixture mounted
thereto portions of the base housing.

[0059]FIG. 39 is a perspective view of the replacement light fixture of
FIG. 37, showing an integral reflector assembly being releasably
connected to the base housing of the light fixture.

[0060]FIG. 40 is an end perspective view of the replacement light fixture
of FIG. 35.

[0061]FIG. 41 is a perspective top view of the integral reflector assembly
of FIG. 35.

[0062]FIG. 42 are exemplary cross-sectional views of the replacement light
fixture of FIG. 35, showing exemplary ranges of adjustability of the
reflector assembly relative to the overlying base housing.

[0063]FIG. 43 is a perspective view of a fifth embodiment of a replacement
light fixture of the present invention, showing the light fixture mounted
to a preexisting light fixture housing in the ceiling.

[0064]FIG. 44 are perspective and cross-sectional views of a bracket for
mounting the replacement light fixture connected to end portions of the
preexisting light fixture housing.

[0065]FIG. 45 are bottom and top perspective views of a light engine of
the replacement light fixture that is configured to mount to the brackets
of FIG. 44, showing the lamps and the ballast of the light engine.

[0066]FIG. 46 is a perspective view of a hinged ballast door that allows
access to the ballast of the light engine and allows for access to power
lines positioned on the top of the light fixture.

[0067]FIG. 47 are perspective and cross-sectional views of a hinge
plate/light trap that is configured to be mounted to a portion of the
bracket of FIG. 44.

[0068]FIG. 48 is a perspective view of the replacement light fixture of
FIG. 44 showing the light sources and the door assembly being installed.

[0069]FIG. 49 is a partial end cross-sectional view of the replacement
light fixture of FIG. 44.

[0070]FIG. 50 is a top perspective view of an exemplary door assembly.

DETAILED DESCRIPTION OF THE INVENTION

[0071]The present invention can be understood more readily by reference to
the following detailed description, examples, drawings, and claims, and
their previous and following description. However, before the present
devices, systems, and/or methods are disclosed and described, it is to be
understood that this invention is not limited to the specific devices,
systems, and/or methods disclosed unless otherwise specified, as such
can, of course, vary. It is also to be understood that the terminology
used herein is for the purpose of describing particular aspects only and
is not intended to be limiting.

[0072]The following description of the invention is provided as an
enabling teaching of the invention in its best, currently known
embodiment. To this end, those skilled in the relevant art will recognize
and appreciate that many changes can be made to the various aspects of
the invention described herein, while still obtaining the beneficial
results of the present invention. It will also be apparent that some of
the desired benefits of the present invention can be obtained by
selecting some of the features of the present invention without utilizing
other features. Accordingly, those who work in the art will recognize
that many modifications and adaptations to the present invention are
possible and can even be desirable in certain circumstances and are a
part of the present invention. Thus, the following description is
provided as illustrative of the principles of the present invention and
not in limitation thereof.

[0073]As used herein, the singular forms "a," "an" and "the" include
plural referents unless the context clearly dictates otherwise. Thus, for
example, reference to a "surface" includes aspects having two or more
such surfaces unless the context clearly indicates otherwise.

[0074]Ranges can be expressed herein as from "about" one particular value,
and/or to "about" another particular value. When such a range is
expressed, another aspect includes from the one particular value and/or
to the other particular value. Similarly, when values are expressed as
approximations, by use of the antecedent "about," it will be understood
that the particular value forms another aspect. It will be further
understood that the endpoints of each of the ranges are significant both
in relation to the other endpoint, and independently of the other
endpoint.

[0075]As used herein, the terms "optional" or "optionally" mean that the
subsequently described event or circumstance may or may not occur, and
that the description includes instances where said event or circumstance
occurs and instances where it does not.

[0076]The present invention may be understood more readily by reference to
the following detailed description of preferred embodiments of the
invention and the examples included therein and to the Figures and their
previous and following description.

[0077]Referring to FIGS. 1-14, in one embodiment of the present invention,
a retrofit light fixture 10 of the present invention for illuminating an
area includes a base assembly 20 for housing a linear light source 12, a
first mounting bracket 50, a second mounting bracket 52, and a reflector
assembly 90. In one aspect, the light source extends along a light
longitudinal axis between a first end 14 and a spaced second end 16.
Light emanating from the light source 12 is diffused by the reflector
assembly 90 that is positioned between the light source 12 and the area
to be illuminated. The light source 12 may be a conventional fluorescent
lamp, such as, for example and not meant to be limiting, a conventional
T5 lamp.

[0078]The base assembly 20 of the retrofit light fixture includes an
elongated base member 22 that has a proximal edge 24, a spaced distal
edge 26, a first longitudinally extending side edge 28 and an opposed
second longitudinally extending side edge 29. The base member 22 extends
along a base member longitudinal axis and has a top surface 30 and a
bottom surface 32. It is contemplated that the base member can be formed
from a single piece of material or from a plurality of adjoined pieces.
As one will appreciate, the base member can be formed from any
code-compliant material. For example, the base member can be formed from
steel.

[0079]In one aspect, the base member defines at least one slot 34 and at
least one aperture 40. In one aspect, the at least one slot is defined
adjacent the proximal edge 24 of the base member and the at least one
aperture 40 is defined adjacent the opposed distal edge 26 of the base
member. It is contemplated that the at least one slot can comprise a
plurality of slots. Similarly, it is contemplated that the at least one
aperture can comprise a plurality of apertures. In one exemplary aspect,
the aperture can be substantially circular is shape. Alternatively, the
aperture 40 can be elongated in at least one axis. For example, the
aperture can have an elongated axis that extends substantially parallel
to the longitudinal axis of the base member.

[0080]In another aspect, at least one of the slots defined in the base
member can form a mounting slot 36 that has a top portion 38 and a bottom
portion 39. In one aspect, the top portion of the mounting slot can be
positioned adjacent the proximal edge of the base member and has a first
dimensional width w1 substantially transverse to the longitudinal
axis of the base member. The bottom portion 39 of the mounting slot has a
second dimensional width w2 substantially transverse to the
longitudinal axis of the base member that is less than the first
dimensional width. In one exemplary aspect, the mounting slot 36 can have
a substantially T shape. It is contemplated that one or more of the slots
of the base member 22 can be formed as a mounting slot. In a further
aspect, it is also contemplated that two or more of the slots can have a
similar size and shape.

[0081]The base assembly 20 can also comprise a plurality of lamp sockets
41 that are selectively mounted to the base member. As one skilled in the
art will appreciate, a pair of opposed lamp sockets can be configured and
positioned on the base member for each elongated linear lamp source that
is to be used in the retrofit light fixture. In a further aspect, the
base assembly 20 can comprise a ballast 42 that is electrically coupled
to the lamp sockets. In one example, the ballast 42 is mounted to a top
surface 30 of the base member such that the ballast is hidden from view
of an external observer when the base member is mounted to the
preexisting light fixture housing 2. In another aspect, a ballast opening
(not shown) can be defined in the base member and a movable access door
cab be provided that is configured to be opened and closed by an operator
to selectively cover the ballast opening. This allows the operator to
access a ballast that is disposed in an interior cavity that is formed
between the top surface of the base housing and portions of the
preexisting light fixture housing. In another aspect, the ballast 42 can
be mounted to a portion of the top surface of the movable access door for
ready access to the ballast by the operator.

[0082]The base member 22 can also define at least one longitudinally
extending trough 44 that extends upwardly away from the respective side
edges 28, 29 of the base member. In one aspect, each trough 44 comprises
a top surface 45, a first side trough surface 46 and an opposed second
side trough surface 47. In another aspect, at least one pair of opposing
lamp sockets can be mounted on the top surface 45 of each trough for
receiving the elongated light source 12. In one aspect, at the trough 44
extends along an axis parallel to the longitudinal axis of the base
member. In one exemplary aspect, and not meant to be limiting, the lamps
sockets can be positioned adjacent the respective proximal and distal
edges 24, 26 of the base member 22.

[0083]Each respective first and second side trough surfaces defines a
trough surface axis that extends in a vertical plane normal to the base
member longitudinal axis of the base member. In one aspect, the trough
surface axis of each of the first and second trough surfaces 46, 47
respectively forms an angle θ of about and between about
140° to 90° with respect to the top surface 45 of the
trough. More particularly, the angle θ can be about and between
about 135° to 95° with respect to the top surface of the
trough. Still more particularly, the angle θ can be about and
between about 130° to 100° with respect to the top surface
45 of the trough. In another aspect, the angle θ formed between
each of the respective first and second trough surfaces and the top
surface of the trough can be substantially equal.

[0084]Referring now to FIGS. 6A-6D, each mounting bracket 50, 52 is
configured for mounting to an edge portion 4 of a respective end wall 6
of the preexisting light fixture housing 2. In one aspect, a lower
portion 54 of the mounting bracket can define a channel 56 that is
configured to be slidably received onto the edge portion 4 of the
respective end wall of the preexisting light fixture housing. In one
aspect, it is contemplated that the channel is configured for a friction
fit with a portion of the respective end wall of the preexisting light
fixture housing. Holes 56 can be defined in the lower portion of each
mounting bracket so that each mounting bracket can be secured to its
respective end wall by use of a conventional mechanical fastener, such
as, for example, a self tapping screw, bolt, or the like. In one aspect,
it is contemplated that each of the respective first and second mounting
brackets can be substantially centered on the respective end walls of the
preexisting light fixture housing.

[0085]In a further aspect, each mounting bracket has an upper shoulder
surface 60 and a medial shoulder surface 62 that is configured to receive
the reflector assembly. In one aspect, the upper and medial shoulder
surfaces extend substantially parallel to the ceiling plane. In another
aspect, at least the first mounting bracket 50 can have at least one male
tab protrusion 64 that extends upwardly away from the upper shoulder
surface 60 that is configured to selectively cooperate with the at least
one slot 34 of the base member 22. In one aspect, the at least one male
tab can be substantially centered relative to the elongated dimension of
the upper shoulder surface of the first mounting bracket. It is
contemplated that the at least one male tab protrusion 64 can comprise a
plurality of male tab protrusions that are configured to selectively
cooperate a complementary plurality of slots 34 of the base member.

[0086]In another aspect, at least one of the male tab protrusions 64
extending from the upper shoulder surface of the first mounting member
can form a mounting male tab protrusion 66 that has a distal end
dimensional width wd that is greater than the dimensional width of a
proximal end portion wp that is connected to the upper shoulder
surface 60. In one exemplary aspect, the mounting male tab protrusion 64
can have a substantially T shape. It is contemplated that one or more of
the male tab protrusions of the first mounting bracket can be formed as a
mounting male tab protrusion. In a further aspect, it is also
contemplated that two or more of the male tab protrusions can have a
similar size and shape. As one skilled in the art will appreciate, the
interconnection of the complementary mounting slot and mounting male tab
protrusion can allow for a secure connection between the base member and
the first mounting bracket that also allows for pivotal movement of the
base member 22 relative to and above the first mounting bracket 50 and
the preexisting light fixture housing 2.

[0087]In one aspect, when mounted thereto the preexisting light fixture
housing 2, each male tab protrusion 64 can extend upwardly at an acute
angle α with respect to a plane parallel to the ceiling plane. In
one aspect, the acute angle α is about and between about 70°
to 90° with respect to the plane parallel to the ceiling plane.
More particularly, the angle α can be about and between about
80° to 90° with respect to the plane parallel to the
ceiling plane. Still more particularly, the angle α can be about
85° with respect to the plane parallel to the ceiling plane.

[0088]In one aspect, the base assembly 20 is movable between an
installation position, in which the base member 22 is suspended from the
first mounting bracket 50 by the cooperative engagement of the at least
one male tab protrusion of the first mounting bracket and the at least
one slot of the base member, and an operating position, in which the base
member 22 is selectively secured to the first and second mounting
brackets 50, 52 by the cooperative engagement of the at least one tab of
the first mounting bracket and the at least one slot of the base member
and the connection of the upper shoulder surface of the second mounting
bracket to a top surface of the base member. In a further aspect, holes
70 can be defined in the upper shoulder surface of the mounting bracket.
In operation, the apertures 40 defined in the base member 22 are
substantially axially aligned with the holes 70 in the upper shoulder
surface so that the upper shoulder surface of the second mounting bracket
can 20 be secured to the top surface of the base member via use of a
conventional mechanical fastener, such as, for example, a self tapping
screw, bolt, or the like.

[0089]It is contemplated that the first and second mounting brackets 50,
52 can have different shapes. However, for ease of installation and for
minimizing production costs, it is preferred that the first and second
mounting brackets can have substantially similar shapes.

[0090]Referring now to FIGS. 4, 5, 8A-9, the longitudinally extending
reflector assembly 90 is configured to be detachable secured to a portion
of the first and second mounting brackets. In one aspect, when it is
secured to the respective first and second mounting brackets, the
reflector assembly is positioned at or above the ceiling plane. In
another aspect, the reflector assembly has a first longitudinally
extending side edge 91 and an opposed second longitudinally extending
side edge 93. In a further aspect, the reflector assembly can be
selectively positioned thereto the first and second mounting brackets
such that the respective longitudinal extending side edges of the
reflector assembly are substantially parallel to or co-planar with the
ceiling plane.

[0091]The reflector assembly 90 further comprises at least one elongated
lens 110. In one aspect, each lens extends longitudinally substantially
parallel to or co-axial with the longitudinal axis of the reflector
assembly. In a further aspect, each lens can be positioned with respect
to a respective trough of the base member such that substantially all of
the light generated or emitted by the light fixture passes through the at
least one lens 110.

[0092]In one aspect, the elongated lens can be replaceably connected to
the reflector assembly. Optionally, the elongated lens can be formed
integrally with the reflector assembly. In another embodiment, the lens
can be separately formed and can then be permanently connected to the
reflector assembly to form an integral body. In various aspects, and as
shown in the figures, it is contemplated that the reflector assembly can
be formed by a conventional vacuum forming process, a conventional
injection molding process, or other conventional processes as known to
one skilled in the art. In one exemplary aspect, the center portion of
the hollow can be cut away and configured to accept a preformed lens,
which can be removably mounted or fixedly mounted as desired. In one
further aspect, it is contemplated that the lenses can be substantially
light transmissive and the reflector portions can be opaque. In a further
aspect, the co-molded lens can include micro optic patters that negate
the need for the use of a diffusing overlay.

[0093]As outlined above, it is contemplated that the reflector and lens
can be, in one example, formed integral to each other or can, in another
example, be separate pieces that can be mounted with respect to each
other and the base housing. In one aspect, the reflector portion of the
reflector assembly is substantially opaque. In another aspect, the
reflectors can have, as described below, a corrugated surface.

[0094]In a further aspect, a reveal can be provided between at least one
edge of the replacement light fixture and the preexisting light fixture
housing such that airflow is allowed when the replacement light fixture
is installed as a replacement for an air handling light fixture. In yet
another aspect, the reflector assembly can be configured to overlap the
T-grid at the respective ends of the replacement light fixture only.

[0095]In a further aspect, a portion of the reflector assembly 90 forms at
least one longitudinally extending hollow 92 that extends inwardly in the
transverse dimension away from the respective first and second
longitudinally extending side edges of the 91, 93 reflector assembly.
Each hollow 92 has a first hollow edge 94 and a second hollow edge 96.
Each hollow extends inwardly to a central portion 98 between the
respective first and second hollow edges 94, 96. In one aspect, the lens
110 is positioned in the central portion of the defined hollow. In one
respect, at least a portion of each hollow 92 preferably forms a
reflective surface 95 extending between central portion 98 and a
respective one of the first and second hollow edges 94, 96. In one
embodiment, at least a portion of a section of each hollow 92 normal to
the base member longitudinal axis has a generally curved shape such that
such that portions of the hollow 92 form a generally curved reflective
surface 95 for diffusely reflecting light received from the lens into the
architectural space in a desired pattern. In one embodiment, the
transverse section of the hollow can have a conventional barrel shape. In
an alternative embodiment, a portion of each hollow 92 can have at least
one planar portion. In one aspect of the invention, the light source 12
can be positioned between the bottom surface of the base member and an
inner surface of the lens.

[0096]In one aspect, at least a portion of the hollow of the base member
can be painted or coated with a reflective material or formed from a
reflective material. The reflective material may be substantially glossy
or substantially flat. In one example, the reflective material is
preferably matte white to diffusely reflect incident light.

[0097]The central portion 98 of the light fixture is preferably
symmetrically positioned with respect to the first and second hollow
edges 94, 96. The retrofit light fixture 10 of the present invention can
include one or more hollows 92 that each houses a light source 12. For
example, in a light fixture having a hollow, the first and second hollow
edges 94, 96 of the hollow would extend generally to the respective
longitudinally extending side edges of the reflector assembly. In an
alternative example, in which the light fixture 10 has two hollows, the
reflector assembly 90 defines a pair of adjoining, parallel hollows 92.

[0098]In one aspect, at least a portion of the hollow(s) 92 of the
reflector assembly 90 has a plurality of male ridges 37 formed thereon
that extend longitudinally between the ends of the base member. In an
alternative aspect, at least a portion of the hollow(s) of the base
member has a plurality of female grooves 39 formed thereon that extend
longitudinally between the ends of the base member. Optionally, the
ridges or grooves extend at an angle to the longitudinal axis of the base
member. For example, the male ridges or female grooves may extend
transverse to the base member longitudinal axis (i.e., extending between
the respective first and second longitudinally extending side edges 91,
93 of the reflector assembly). The ridges or grooves formed on the hollow
provide a diffusely reflecting surface.

[0099]As shown in FIG. 13, the reflector assembly 90 can also include a
first end face 100 and an opposed second end face 102. Each of the end
faces extends upwardly from a respective bottom end edge other reflector
assembly to respective ends edges 112, 113 of the lens. Each end face has
a face longitudinal axis that forms an obtuse angle with respect to the
longitudinal axis of the reflector assembly 90. The angled first and
second end faces 100, 102 optically alter the apparent perspective of the
light fixture and aesthetically give the light fixture a deeper
appearance.

[0100]In one aspect, the face longitudinal axis of each of the first and
second end faces 100, 102 respectively forms an angle Ω of about
and between 95° to 160° with respect to the longitudinal
axis of the reflector assembly. More particularly, the face longitudinal
axis of each of the first and second end faces respectively forms an
angle Ω of about and between 100° to 150° with
respect to the longitudinal axis of the reflector assembly. Still more
particularly, the face longitudinal axis of each of the first and second
end faces respectively forms an angle Ω of about and between
100° to 135° with respect to the longitudinal axis of the
reflector assembly. In another aspect, the face longitudinal axis of each
of the first and second end faces respectively forms an angle Ω of
about 120° with respect to the longitudinal axis of the reflector
assembly. In yet another aspect, the respective obtuse angles formed
between the face longitudinal axis of the first end face 50 and the face
longitudinal axis of the second end face 52 and the longitudinal axis of
the reflector assembly are substantially equal.

[0101]Alternative shapes of the first and second end faces 100, 102 are
contemplated. Each of the first and second end faces may be substantially
planar or non-planar. In the non-planar embodiments, portions of the
first and second end faces are curved. The curved portions of the first
and second end faces can be substantially concave or substantially
convex. Portions of the first and second end faces can also have male
ridges or female grooves formed thereon. The male ridges or female
grooves can be sized, shaped and oriented to visually complement the male
ridges or female grooves 39 on the hollows or the reflector assembly, as
described above.

[0102]The retrofit light fixture 10 of the present invention also can
comprise means for selectively pivotably securing the reflector assembly
to the first and second mounting brackets. In one aspect, a plurality of
bias members 80 and a plurality of latches 84 are provided that allow for
the hinging motion of the reflector assembly 90 relative to the first and
second mounting brackets 50, 52, and hence the preexisting light fixture
housing 2, and the selective securing of the reflector assembly to the
first and second mounting brackets. Referring to FIGS. 8-10, an
exemplified bias member and a rotatable latch are illustrated. It will be
appreciated by one skilled in the art that conventional spring members
and latches can be used in the present application.

[0103]In one exemplary aspect, a bore 82 is defined in each peripheral end
edge of the reflector assembly 90 that can be positioned substantially
co-axial to complementary openings 83 that are defined in the lower
portion of both the first and the second mounting brackets 50, 52. In
this aspect, an arm 81 of the bias member 80, which is operatively
coupled to an interior portion of the end edge of the reflector assembly,
is configured to selectively engage each aligned bore and openings. In
another exemplary aspect, each latch 84 is pivotably mounted to each
peripheral end edge of the reflector assembly 90 and is configured to
selectively, by rotation by the installer, engage a latch slot 85 that is
defined in the lower portion of each mounting bracket 50, 52.

[0104]It will be appreciated that the opening in the mounting brackets can
comprise a pair of openings that are positioned adjacent the opposing
ends of the mounting brackets 50 that the installer can selectively
determine, based on the space and environmental concerns in the work
space, from which side of the respective mounting bracket it is desired
to have the reflector assembly hinged to. In this aspect, the latch slot
can comprise a pair of latch slots that are symmetrically positioned
about the center of the respective mounting bracket.

[0105]In one aspect, in operation, portions of each of the first and
second end faces 100, 102 can be positioned in overlying registration
with at least a portion of a selected end of the light source 12. The
brighter conventional lamps, such as the exemplified T5 lamp, are
typically shorter and have an elongated dark portion proximate its ends
when compared to other conventional elongated fluorescent lamps, such as,
for example, conventional T8 and T12 lamps. Thus, in use, the end faces
can prevent the darkened ends of the selected light source from being
visible through the lens assembly.

[0106]The lens 110 of the present invention is constructed and arranged to
direct light emitted by the light source 12 onto the area to be
illuminated. A basic function of the lens 110 is to diffuse the light
from the light source 12 to effectively reduce the brightness of the
light source 12 so that it is substantially hidden from view. Thus, one
function of the lens assembly is to effectively become the source of
light for the light fixture. This is accomplished in the preferred
embodiment by providing the lens 110 with a plurality of longitudinally
extending prismatic elements with short focal lengths. Because of the
short focal lengths of the prismatic elements, the light from the light
source is focused to parallel images very close to the surface of the
lens at large angles of convergence. Because of the large angles of
convergence, the images overlap and the light is essentially diffused.
The diffused light is then either directed onto the surface to be
illuminated without further reflection or is reflected by the reflective
surfaces of the hollow 95. Thus, the lens provides a diffuse source of
lowered brightness.

[0107]In one aspect, the lens can be placed higher in the retrofit light
fixture and provides geometric control of high-angle rays emanating from
the lens in the transverse direction. Thus, light rays produced at high
viewing angles are physically blocked by the bottom longitudinally
extending side edges of the reflector assembly, which prevents glare at
high angles in that transverse direction. The retrofit light fixture of
the invention can, in an optional aspect, control glare in the
longitudinal direction optically.

[0108]As discussed and illustrated in applicants' co-pending U.S. patent
application Ser. Nos. 10/970,615 and 10/970,625, the disclosures of which
are incorporated herein in their entireties by this reference, high angle
glare is reduced in the retrofit light fixture of the present invention.
Thus, in this aspect, the retrofit light fixture of the invention
prevents glare at high viewing angles through two mechanisms,
geometrically in the transverse direction and optically in the
longitudinal direction.

[0109]In one aspect, the lens 110 comprises a first end edge 112 and an
opposed second end edge 113. The lens has a lens longitudinal axis that
extends between the first and second end edges. In one example, the lens
longitudinal axis is generally parallel to the light longitudinal axis of
the light source 12. In use, substantially all of the light emitted by
the light source 12 passes through the lens 110 prior to impacting
portions of the reflective surfaces 95 of the reflector assembly and/or
prior to being dispersed into the surrounding area.

[0110]The lens 110 can be made from any suitable, code-compliant material
such as, for example, a polymer or plastic. For example, the lens 110 can
be constructed by extruding pellets of meth-acrylate or polycarbonates
into the desired shape of the lens. The lens 110 can be a clear material
or translucent material. In another aspect, the lens can be colored or
tinted. It is contemplated that the reflector portion 111 of the
reflector assembly as well as the lens can be substantially formed from
plastic or polymer materials for both significant cost and weight
savings. In one aspect, the lens provides structural support for a
plastic and/or polymeric reflector portion such that the reflector
assembly is self supporting and does not necessarily require the use of
metal supports, such as, for example, a peripherally extending metal
frame.

[0111]At least a portion of the lens has a prismatic surface 116 on a face
118 of the lens that is either spaced from and facing toward the light
source 12 or, alternatively, spaced from and facing away from the light
source 12. In one aspect of the invention, the lens is curved in
cross-section such that at least a portion of the face 118 of the lens
has a concave or convex shape relative to the light source. In an
alternative embodiment, at least a portion of the lens is planar in
cross-section.

[0112]In one aspect, the lens 110 is positioned within the reflector
assembly so that it is recessed above a substantially horizontal plane
extending between the first and second longitudinally extending side
edges of the reflector assembly. In a further aspect, the lens is
recessed within the reflector assembly such that a plane bisecting one of
the respective first and second longitudinally extending side edges of
the preexisting light fixture housing or, optionally, of the reflector
assembly, and a tangential portion of the lens is oriented at an acute
angle γ to the generally horizontal plane extending between the
selected first and second longitudinally extending side edges. In one
aspect, the acute angle γ is about and between 3° to
30°. More particularly, the acute angle γ is about and
between 05° to 20°. Still more particularly, the acute
angle γ is about and between 10° to 15°.

[0113]The recessed position of the lens within the reflector assembly
provides for high angle control of light emitted by the retrofit light
fixture in a vertical plane normal to the longitudinal axis of the
reflector assembly. In use, an observer approaching the ceiling mounted
retrofit light fixture 10 of the present invention from the side (i.e.,
from a direction transverse to the longitudinal axis of the reflector
assembly) would not see the lens until they passed into the lower viewing
angles. In effect, portions of the reflector assembly act to block the
view of the lens from an observer at the higher viewing angles (i.e., the
viewing angles closer to the horizontal ceiling plane).

[0114]In one aspect, as shown in FIGS. 18-21, the prismatic surface 116 of
the lens defines an array of linearly extending prismatic elements 120.
In one example, each prismatic element 122 thereof can extend
substantially longitudinally between the first and second edge edges 112,
113 of the lens. Alternatively, each prismatic element 122 thereof can
extend linearly at an angle relative to the lens longitudinal axis. For
example, each prismatic element thereof can extend generally transverse
to the lens longitudinal axis. In a further aspect, each prismatic
element 122 can have substantially the same shape or, alternatively, can
vary in shape to effect differing visual effects on an external observer,
lighting of the hollow surface, or light distribution to the room. In one
aspect, each prismatic element has a portion that is rounded or has a
curved surface.

[0115]In one aspect, in section normal to the lens longitudinal axis, each
prismatic element has a base 124 and a rounded apex 126. Each prismatic
element extends toward the apex 126 substantially perpendicular with
respect to a tangent plane that extends through the base 124. In one
aspect, an arcuate section or curved surface 128, normal to the lens
longitudinal axis, of each prismatic element 122 subtends an angle β
of about and between 85° to 130° with reference to the
center of curvature of the arcuate section. More particularly, the
arcuate section 128 of each prismatic element forms an angle β of
about and between 90° to 120°. Still more particularly, the
arcuate section 128 forms an angle β of about and between 95°
to 110°. In another aspect, the arcuate section 128 forms an angle
β of about 100°.

[0116]In one aspect, the arcuate section 128 extends from a first cusp
edge 130 of the prismatic element 122 to an opposed second cusp edge 132.
In this example, adjoining prismatic elements are integrally connected at
a common cusp edge 130, 132, 133. Alternatively, the arcuate section 128
may be formed in a portion of the apex 126 of the prismatic element 122,
such that adjoining prismatic element are integrally connected at a
common edge 133. In this example, portions of the prismatic element 122
extending between the arcuate section and the common edge 133 can be
planar or non-planer, as desired. It should be understood that other
configurations and shapes are contemplated where the cross section of the
optical elements is not strictly circular, and includes, for example,
parabolic, linear, or other shapes.

[0117]In one aspect, the base 124 of each prismatic element 122 has a
width (w) between its respective common edges of about and between 0.5
inches to 0.01 inches. More particularly, the base of each prismatic
element has a width between its respective common edges of about and
between 0.3 inches to 0.03 inches. Still more particularly, the base of
each prismatic element has a width between its respective common edges of
about and between 0.15 inches to 0.05 inches.

[0118]In another aspect, a section of the array of prismatic elements 120
can have a shape of a continuous wave. The section can be normal to the
lens longitudinal axis. In one aspect, the shape of the continuous wave
is a periodic waveform that has an arcuate section 128 formed in both the
positive and negative amplitude portions of the periodic waveform (i.e.,
two prismatic elements are formed from each periodic waveform). The
period of the periodic waveform can be substantially constant or may vary
along the array of prismatic elements. In one aspect, the periodic
waveform is a substantially sinusoidal waveform. In this example, the
common cusp "edge" 130,132 between the two prismatic elements 122 forming
from each periodic waveform occurs at the transition from
positive/negative amplitude to negative/positive amplitude.

[0119]In one aspect, the arcuate section 128 of each prismatic element 122
within each of the positive and negative amplitude portions of the
periodic waveform subtends an angle λ, of about and between
85° to 130° with reference to a center of curvature of the
arcuate section. More particularly, the arcuate section 128 of each
prismatic element within each of the positive and negative amplitude
portions of the periodic waveform forms an angle λ of about and
between 90° to 120°. Still more particularly, the arcuate
section 128 of each prismatic element within each of the positive and
negative amplitude portions of the periodic waveform forms an angle
λ, of about and between 95° to 110° with respect to
the base member longitudinal axis. In another aspect, the arcuate
sections 128 within each of the positive and negative amplitude portions
of the periodic waveform form an angle λ, of about 100°.

[0120]In one aspect, the period P of each prismatic element is about and
between 1.0 inches to 0.02 inches. More particularly, the period P of
each prismatic element is about and between 0.6 inches to 0.06 inches.
Still more particularly, the period P of each prismatic element is about
and between 0.30 inches to 0.10 inches.

[0121]It is contemplated that the lens 110 of the reflector assembly 100
can be constructed and arranged for detachable connection to the
reflector assembly of the light fixture 10. Optionally, the lens of the
reflector assembly can be integrally formed with the reflector assembly.
In one aspect, when positioned relative to the base member 22, the lens
of the reflector assembly can extend generally parallel to the light
longitudinal axis and generally symmetric about a plane that extends
through the light longitudinal axis. In one other aspect, the plane of
symmetry extends through the area desired to be illuminated.

[0122]In a further aspect, the reflector assembly can further comprise a
conventional diffuser inlay 150, such as, for example, a OptiGrafix®
film product, which is a diffuser film that can be purchased from
Grafix® Plastics. The diffuser inlay 150 can be pliable or fixed in
shape, transparent, semi-translucent, translucent, and/or colored or
tinted. In one example, the diffuser inlay 150 has relatively high
transmission efficiency while also scattering a relatively high amount of
incident light to angles that are nearly parallel to its surface. In one
aspect, the diffuser inlay is positioned between a portion of the face
118 of the lens and the light source 12. In another aspect, the diffuser
inlay is configured for positioning in substantial overlying registration
with the portion of the face 118 of the lens that is oriented toward the
light source 12.

[0123]In a further aspect, the diffuser inlay 150 may be positioned in
substantial overlying registration with a portion of the prismatic
surface 116 of the lens. In one aspect of the present invention, there is
a gap 152 formed between portions of the two adjoining rounded prismatic
elements 120 extending between the respective apexes of the two adjoined
prismatic elements and the bottom face 151 of the diffuser inlay 150. The
formed gap can enhance the total internal refection capabilities of the
lens 110.

[0124]The lens 110 and reflector assembly 20 of the present invention
increases the light efficiency of the light fixture 10 and diffuses the
light relatively uniformly so that the "cave effect" commonly noted in
areas using conventional parabolic light fixtures in the ceiling are
minimized. In one embodiment, the light fixture 10 or troffer of the
present invention results in a luminare efficiency that is greater than
about 80%, preferably greater than about 85%. The efficiency of the light
fixture 10 measured by using a goniophotometer to compare the light
energy from the light fixture at a given angle with the light from an
unshielded light source, as specified in the application testing
standard. The retrofit light fixture 10 of the present invention has
reduced light control relative to conventional parabolic fixtures to
provide a lit space (particularly the walls) with a bright appearance
while still maintaining adequate control and comfortable viewing for
today's office environment.

[0125]In one embodiment, the lens 110 has a concave face 118 oriented
toward the light source 12 when the lens 110 is secured to and within a
portion of the reflector assembly 20. In one aspect, the array of male
rounded prismatic elements 120 can be extruded along the length of the
lens 110. In use, the lens of the present invention design has a striped
visual characteristic to an external observer when back lit. These
"stripes" provide for visual interest in the lens 110 and may be sized
and shaped to mirror any ridges or grooves disposed therein portions of
the reflective surfaces 33 of the hollow 32 of the reflector assembly 20.
The "stripes" also help to mitigate the appearance of the image of the
lamp (the light source) by providing strong linear boundaries that
breakup and distract from the edges of the lamp against the less luminous
trough 40 of the reflector assembly 20. In addition, the "stripes" allow
for the retrofit light fixture 10 of the present invention to provide
high angle light control in vertical planes that are substantially
parallel to the longitudinal axis of the light fixture.

[0126]In a preferred embodiment, a primary function of the lens is to
optically reduce the brightness of the light source. In addition, the
lens reduces the brightness of the light source even further at higher
viewing angles in the longitudinal direction by the optical phenomenon of
total internal reflection. This allows the efficient use of light sources
of higher brightness while nevertheless reducing glare at high viewing
angles.

[0127]It will be appreciated that the retrofit light fixture of the
invention utilizes a unique combination of features to reduce high-angle
glare in the transverse and longitudinal directions. In the transverse
direction, high angle glare is controlled primarily by the geometric
relationship between the lamp and the reflector assembly of the retrofit
light fixture, while in the longitudinal direction, high angle glare is
controlled primarily by the lens optically. In the preferred embodiment,
the lens itself essentially becomes the light source, which effectively
reduces lamp brightness in both the transverse and longitudinal
directions optically, to further reduce glare associated with lamps of
high brightness.

[0128]One skilled in the art will appreciate that a "reverse ray,"
"backward ray" or "vision ray" is a light ray that originates from a
hypothetical external viewer's eye and is then traced through the optical
system of the light fixture. Although there is no physical equivalent, it
is a useful construct in predicting how a particular optical element will
look to an observer. In the present invention, on at least one side at
the respective common cusp edges of adjoining rounded prismatic elements,
there exists a sufficiently large angle of incidence ω relative to
the normal extending from the point of incidence of the reverse ray at
the lens to air interface that a reverse ray will undergo total internal
reflection. In one aspect, the angle of incidence ω is at least
about 40°. More particularly, the angle of incidence ω is at
least about 45°. Still more particularly, the angle of incidence
ω is at least about 50°. In effect, the array of prismatic
elements acts as an array of partial light pipes.

[0129]Each rounded prismatic element has a sufficiently large angular
extent such that some total internal reflection at each common cusp edge
is assured regardless of viewing angle. In one aspect, since each arcuate
section of each rounded prismatic element is substantially circular, if a
reverse ray undergoes total internal reflection at one portion of the
arcuate section and is subsequently reflected to another portion of the
arcuate section, then total internal reflection will also occur at the
second point of incidence because the arcuate section's geometry causes
both interactions to have substantially the same angle of incidence.
Generally then, a reverse ray that undergoes total internal reflection
proximate a common cusp edge will eventually exit the lens out the same
outer surface through which it entered the lens and will terminate on a
surface or object in the room (as opposed to passing through the lens and
terminating on the light source or the trough of the reflector assembly
behind the lens). The reverse ray is said to be "rejected" by the lens.
This means that the brightness an external viewer will perceive at the
common cusp edge of adjoining rounded prismatic elements is the
brightness associated with a room surface because any real/forward light
ray impinging on the viewer's eyes from this part of the lens must have
originated from the room or space. Generally, the brightness of an object
or surface in the room is much lower than that of the light source or
trough that is viewed through the central portions of the arcuate
sections of each prismatic element. This high contrast in brightness
between the common cusp edge between adjoining rounded prismatic elements
and the central portion of the arcuate sections of each prismatic element
is so high that it is perceived, to the external viewer, as dark stripes
on a luminous background.

[0130]In another aspect, the linear array of prismatic elements of the
lens assembly optically acts in the longitudinal direction to reduce high
angle glare. This may be explained by considering a reverse ray that is
incident on a portion of the prismatic surface of the lens proximate the
common cusp edge at the critical angle (the minimum angle of incidence
ω) for total internal reflection of the reverse ray. An observer
viewing that portion of the lens (i.e., the portion of the area about the
common cusp edge) would perceive it as being "dark" relative to that
adjacent "bright" portion of the arcuate section proximate the rounded
apex of each individual prismatic element. The array of linear elements
thus optically controls the light emitted from the lamp in the
longitudinal direction.

[0131]In one example, as the lens is viewed at higher and higher viewing
angles (as when the observer is further from the light fixture) in a
vertical plane parallel or near parallel to the base member longitudinal
axis of the base member, the striping effect become more pronounced. This
is a result of the increase in that portion of the prismatic surface of
the lens that undergoes total internal reflection and creates the dark
strips. This results from viewing the lens at angles greater than the
critical angle for total internal reflection of a "reverse ray." Thus,
the effective width of each stripe grows as the lens is viewed at higher
viewing angles, which is observed as the lens becoming dimmer at higher
viewing angles.

[0132]In the vertical planes extending between the base member
longitudinal axis of the reflector assembly and an axis transverse to the
base member longitudinal axis, higher view angle control is achieved
through a combination of the high angle control proffered by the linearly
extending array of prismatic elements of the lens, as discussed
immediately above, and the lens assembly being recessed within the
reflector assembly. In the vertical plane substantially parallel to the
base member longitudinal axis of the reflector assembly, the optical
elements of the lens assembly, i.e., the array of prismatic elements,
exert primary glare control of the higher viewing angles. In the vertical
plane substantially transverse to the base member longitudinal axis of
the reflector assembly, the recessed position of the lens assembly within
the reflector assembly exerts primary glare control of the higher viewing
angles.

[0133]In one aspect, if the prismatic shapes are regularly spaced apart,
the striping effect would also be regularly spaced. In another aspect,
the prismatic elements of the present invention can be configured as
desired to ensure some total internal reflection at all viewing angles so
that the "striping" is perceptible at all viewing angles.

[0134]In use, normal movement of a viewer in the room does not change the
viewer's vertical angle of view relative to the light fixture very
rapidly and at far distances the stripes become less distinct. Therefore,
the change is stripe width is not perceived as a dynamic motion but
rather as a subtle changing of the overall lens brightness (i.e.,
brighter at low vertical angles and dimmer when viewed at high vertical
angles).

[0135]The rounded or curved surfaced portions of each prismatic element
can provide wide spreading or diffusion of any incident light. The high
degree of diffusion helps to obscure the image of the light source as
seen through the lens even when the light source is in relatively close
proximity to the face of the lens that is oriented toward the light
source. This becomes increasingly apparent as the lens is viewed at
higher vertical angles in the vertical plane substantially parallel to
the light source.

[0136]In a further aspect, the rounded or curved surface portions of the
prismatic elements provides for a gradual change in the perceived
brightness as a result of a change in the angle of view. In yet another
aspect, in an embodiment of the invention in which each prismatic element
has substantially the same shape, the dark striping and the brighter
areas of the lens appear to change uniformly and smoothly from one
prismatic element to the next, adjoining prismatic element.

[0137]As described above, the present invention relates to a replacement
or retrofit light fixture 10, or troffer, for efficiently distributing
light emitted by a light source into an area to be illuminated. As
described above, the lens 110 and reflector assembly 90 of the retrofit
light fixture increases the light efficiency of the replacement or
retrofit light fixture and diffuses the light relatively uniformly, which
minimizes the "cave effect" commonly noted in areas using conventional
parabolic light fixtures in the ceiling. For example, it is estimated
that the replacement of a conventional 3 lamp parabolic troffer with a
retrofit light fixture 10 of the present invention would result in an
annual energy savings of about 170 kWh. For the replacement of a
conventional 4 lamp parabolic troffer, the annual energy savings of about
526 kWh is estimated.

[0138]In one aspect of the present invention, and as one skilled in the
art will appreciate, the design of the base assembly enables attachment
of the retrofit ballast and lamp sockets to the base member and the
electrical wiring connection between the retrofit ballast and lamp
sockets to be performed during a manufacturing process at a factory.
Thus, the installer does not have to devote time or labor to these tasks.
As further shown in FIG. 11, the retrofit light fixture can also comprise
power leads that are configured for connection to the preexisting power
leads extending from the preexisting light fixture housing. Further, and
as shown in FIG. 11, in compliance with electrical code requirements, the
retrofit light fixture can also comprise a ground lead configured to
electrically couple the base member to the preexisting light fixture
housing and a splice box that is configured to mount to the bottom
surface of the preexisting light fixture housing and can operatively
accept the power leads extending from the retrofit ballast.

[0139]Installation of the exemplary embodiment of the retrofit into the
existing fixture is illustrated in FIGS. 10 through 16. One skilled in
the art will appreciate that the following steps can be accomplished by a
one-man installation crew, which allows for additional cost savings.
Exemplary steps are as follows.

[0140]First, power must be disconnected to the existing fixture. Then the
existing lamps, reflector, ballast of the existing light fixture can be
removed, which leaves the existing power leads extending therein the
internal cavity of the preexisting light fixture housing exposed. As one
will appreciate, these existing power leads are electrically coupled to a
conventional remote power source. The next step is to mount the
respective first and second mounting brackets to the edge portions of the
respective opposing end walls of the preexisting light fixture housing.
The mounting brackets can then be mechanically secured to the preexisting
light fixture. In one aspect, the mounting brackets are substantially
centered on the respective end walls.

[0141]The next installation step is to hang the base member from first
mounting bracket by it's at least one male tab protrusion. This can be
accomplished by inserting the at least one male tab protrusion within
it's complementary at one slot of the base member. In one aspect, the
mounting male tab protrusion is inserted into the mounting slot of the
base member. The base member can be released so that it is supported in
the installation position by the first mounting bracket.

[0142]The power lines for the ballast of the base assembly can then be
coupled to the existing power leads. Optionally, the grounds from the
base member to the preexisting light housing can be attached. In a
further aspect, a splice box can be mounted to a surface of the
preexisting light housing such that a portion of the coupled power leads
pass therethough the splice box. After the wiring connections are
complete, the installer may then swing the base member up into place so
that the at least one aperture of the base member is positioned in
substantially overlying registration with the holes 70 that are defined
in the upper shoulder surface of the second mounting bracket 52.
Subsequently, a portion of the top surface of the base member is
mechanically connected to the upper shoulder surface of the second
mounting bracket. In a further aspect, if not previously installed, the
light source(s) 12 can be mounted to the light sockets that are mounted
on the base member.

[0143]It will be appreciated, that if the first and second mounting
brackets are similarly shaped, the base member would be initially
hingeably hung from the respective mounting member that is closest to the
existing power lead opening in the preexisting light fixture housing.

[0144]Next, the reflector assembly is coupled to the mounting brackets. In
one aspect, the installer makes initial decision as to the desired
direction for hingeable opening of the reflector assembly. Subsequently,
the installer inserts the bias members 80 of the reflector assembly
thereto the respective openings 83 that are defined in the lower portion
of both the first and second mounting brackets. In one exemplary aspect,
and as shown in FIGS. 8A and 8B, the arm 81 of the bias member has a
substantially cross-sectional rectangular shape and the respective
opening has a substantially circular shape so that the arm will tend to
self-center its self when it is inserted into the opening 83. The
reflector assembly is then rotated about the formed hinge to seat against
the medial shoulder surface of the mounting brackets and the latch of the
reflector assembly is rotated to engage the latch slot 85 in the lower
portion of each mounting bracket 50, 52 to selectively secure the
reflector assembly relative to the mounting brackets and the preexisting
light fixture housing.

[0145]Referring now to 23-50, exemplary alternative embodiments of the
present invention suitable for retrofit or replacement of preexisting
ceiling light fixtures are described. In one embodiment, suitable for
retrofit or replacement applications, the present invention relates to a
downlight replacement light fixture 200 for efficiently distributing
light emitted by a light source into an area to be illuminated that can
be mounted in a preexisting light fixture housing 202, which can be, in
one aspect, conventionally mounted therein a ceiling.

[0146]In one exemplary embodiment, the replacement light fixture 200 of
the present invention can comprise a base housing 210 that is configured
to mount to the preexisting light fixture housing. In one aspect, the
base housing is configured to receive at least one light source 12 that
is releasably mounted to lamp sockets 41, which are connected to portions
of the base housing. In yet another aspect, the replacement light fixture
can comprise a reflector assembly that is mounted to and underlies the
base housing of the replacement light fixture.

[0147]In another aspect, a ballast 42 is provided that is, in at least one
embodiment, connected to the base housing 210 and is in operable
connection with the lamp sockets 41 to selectively energize the at least
one light source 12. In this aspect, it is contemplated that the lens of
the replacement light fixture is positioned with respect to a portion of
the reflector to receive light emitted by the light source 12 and
distribute it such that glare is further reduced. In a preferred
embodiment, the lens 110 of the exemplary retrofit light reflectors
receives and distributes substantially all of the light emitted by the
light source. In at least one aspect, the lens 110 of the replacement
fixture has the characteristics of the lens 110 described above.

[0148]Turning to FIGS. 23 and 25, a first embodiment of an exemplary
replacement light fixture 200 is illustrated. In this embodiment, the
base housing 210 is coupled to the reflector assembly. After the louver,
lamps, ballast and ballast cover of the preexisting light fixture are
removed, the original, the preexisting lamp fixture housing 2 of the
preexisting fixture remains mounted therein the ceiling. In this
application, an edge of the base housing of the replacement light fixture
is pivotally connected to an edge of the preexisting light fixture
housing. In one example, one longitudinal edge of the base housing is
pivotally connected, via a hinge, to a longitudinal edge of the
preexisting light fixture housing. Alternatively, the respective end
edges of the base housing and the preexisting light fixture housing are
pivotally connected together. A means of selectively securing the base
housing 210 of the replacement light fixture relative to the preexisting
light fixture housing 2 is also provided so that the face of the
replacement light fixture lies in a desired plane relative to the
ceiling. In this aspect, for example, the base housing can be configured
to be generally fit the peripheral size and shape of the preexisting
light fixture housing. In another aspect, the base housing and reflector
assembly are provided as an integral unit to be pivotally mounted therein
the preexisting light fixture housing.

[0149]In one aspect of this embodiment, the replacement light fixture 200
is electrically coupled to the preexisting ballast of the preexisting
light fixture. In an alternative aspect, the ballast 42 of the fixture
can be mounted in an internal cavity of the fixture and is electrically
coupled to the preexisting exterior power source. In yet another aspect,
as shown in FIG. 25, the ballast 42 can be mounted to a portion of the
exposed bottom surface of the preexisting light fixture housing. In yet
another aspect, the ballast 42 can be mounted to the top surface of the
housing. As one will appreciate, in the latter two aspects, the ballast
42 is readily accessible for repair by simply opening and pivoting the
replacement light fixture 200 relative to the preexisting light fixture
housing 202. Further, in the latter two aspects, the replacement light
fixture 200 is configured to be spaced from the bottom surface of the
preexisting light fixture housing a distance such that an adequate
internal cavity is formed for receipt of the ballast.

[0150]Referring now to FIGS. 26-28, a second embodiment of a replacement
light fixture is illustrated. In this exemplary embodiment, the base
housing 210 of the replacement light fixture is connected to a portion of
a preexisting light fixture housing. In one aspect, the base housing 210
of this embodiment has a first reflector piece 213 that overlies and
partially surrounds the light source. The base housing further has a pair
of opposing downwardly extending longitudinal side walls 214 that are
symmetrically spaced from the longitudinal axis of the base housing. In
one aspect, the ballast 42 is mounted to a portion of one of the
downwardly extending side walls. In a further aspect, the base housing
210 is mounted to the preexisting light fixture housing such that the
base housing extends substantially along the longitudinal axis of the
preexisting light fixture housing 2.

[0151]The reflector assembly of the replacement light fixture 200 of this
embodiment comprises a pair of opposing, complementary reflector members
262, a pair of lock members 264, and a lens 110. In one aspect, the
reflector members are mounted to respective portions of the longitudinal
side walls 213 of the base housing 210 and the walls of the preexisting
light fixture housing such that the reflector members 262 are positioned
symmetrically with respect to the mounted base housing 210 and underlie
portions of the preexisting light fixture housing. Thus, in one aspect,
the reflector members 262 are installed between the top of the T-grid and
the bottom of the preexisting light fixture housing. Of course, it is
contemplated that the reflector members can have any desired shaped. In
one example, as illustrated, the longitudinally extending walls of the
reflector members are curved, at least in portion, and the "end faces" of
the respective reflector members are angled with respect to the
longitudinal axis of the replacement fixture. In one aspect, at least a
portion of the reflector members 262 can be painted or coated with a
reflective material or formed from a reflective material. The reflective
material may be substantially glossy or substantially flat. In one
example, the reflective material is preferably matte white to diffusely
reflect incident light.

[0152]To secure the reflector members relative to the base housing 210 and
the preexisting light fixture housing, each lock member 264, configured
for a friction fit, is mounted to the respective opposing edges of the
end faces of the reflector members, the base housing, and the preexisting
light fixture housing. Finally the curved lens is mounted to the base
housing 210 such that substantially all of the light generated by the
light source 12 passes through the lens of the replacement fixture.

[0153]Referring now to FIGS. 29-34, a third embodiment of the replacement
light fixture of the present invention is disclosed. In this embodiment,
the base housing 210 defines a pair of longitudinally extending and
downwardly facing troughs 215. Each trough is configured to accept a
longitudinally extending light source 12. In another aspect, the pair of
troughs 215 is substantially parallel to each other. In another aspect,
the base housing 210 further comprises a generally planar member 216 that
extends between portions of the pair of longitudinally extending troughs
215 so that the longitudinal axis of the troughs are spaced a
predetermined distance apart. The base housing 210 is configured to mount
to a bottom surface of the preexisting light fixture housing so that the
base housing is symmetrically positioned with respect to the preexisting
light fixture housing.

[0154]In one aspect, the generally planer member 216 and portions of the
opposing troughs 215 define a channel 217 forming an interior cavity 218.
In one example, the conventional ballast 42 is mounted to a top surface
211 of the base housing 210 such that the ballast is hidden from view of
an external observer when the base housing is mounted to the preexisting
light fixture housing. In one aspect, a movable cover 219 is provided on
the planar member that is adapted to be opened and closed by an operator
to access a ballast 42 that is disposed in the interior cavity 218 formed
between the top surface 211 of the base housing 210 and portions of the
preexisting light fixture housing. In another aspect, the ballast 42 can
be mounted to a portion of the top side of the movable cover 219 for
ready access to the ballast by an operator.

[0155]In this aspect, after the base housing is mounted to the preexisting
light fixture housing and the ballast is accessed and connected to the
preexisting power leads, the reflector assembly is mounted to the base
housing 210 such that it substantially underlies the base housing and
fully encloses the fixture. In this aspect, it is contemplated that the
reflector portion 111 and lens 110 can be, in one example, formed
integral to each other or can, in another example, be separate pieces
that can be mounted with respect to each other and the base housing 210.
In one aspect, the reflector portion 111 of the reflector assembly is
substantially opaque.

[0156]In one aspect, the longitudinally extending sides 220 of the troughs
215 are mounted to the base housing by means that allow the sides 220 of
the trough to be self-adjusting in height. In one exemplary aspect, the
each side can have a plurality of vertically oriented slots defined
therein. These slots are in operable communication with complementary
bias members that extend from respective portions of the base housing
210. Thus, the replacement fixture 200 of the present invention can be
used in preexisting light fixture housing of varying depth as the
adjustable sides of the troughs of the base housing articulate so that
they are in contact with or are adjacent to top portions of the reflector
assembly.

[0157]Referring now to FIGS. 35-42, a fourth embodiment of a replacement
light fixture of the present invention is illustrated. In this
embodiment, the base housing 210 has a pair of longitudinally extending
and downwardly facing side edges 224. In one aspect, the conventional
ballast 42 is mounted to a bottom surface 212 of the base housing. A
formed channel cover 225 is provided that is configured to mount between
the light sources 12 such that the ballast is hidden from view of an
external observer when the channel cover 225 is attached to the base
housing 210. In another aspect, the respecting side edges and the sides
of the formed channel cover defines a pair of longitudinally extending
and downwardly facing troughs 227. As one will appreciate, each trough is
configured to accept one longitudinally extending light source 12. In
another aspect, the pair of troughs is substantially parallel to each
other. In another aspect, the longitudinal axes of the troughs 227 are
spaced a predetermined distance apart. The base housing 210 is configured
to mount to a bottom surface of the preexisting light fixture housing so
that the base housing is symmetrically positioned with respect to the
preexisting light fixture housing.

[0158]In this aspect, after the base housing 210 is mounted to the
preexisting light fixture housing and the ballast is accessed and
connected to the preexisting power leads, the reflector assembly is
mounted to the base housing such that it substantially underlies the base
housing 210 and fully encloses the fixture. In this aspect, it is
contemplated that the reflector portion and lens of the reflector
assembly can be, in one example, formed integral to each other or can, in
another example, be separate pieces that can be mounted with respect to
each other and the base housing. In one aspect, the reflector portion of
the reflector assembly is substantially opaque. Referring to FIG. 41, the
reflector assembly can further comprise at least one longitudinally
extending and upwardly extending light bar members 265 that cooperate
with portions of the base housing 210 to direct the light generated by
the light sources. Thus, as shown in FIG. 42, in one aspect, the light
bar members 265 allow for the use of the replacement fixture of the
present invention in preexisting light fixture housing of varying depth
as the light bar helps to direct the generated light through the lens 250
of the reflector assembly.

[0159]In a further aspect, a reveal 270 can be provided between at least
one edge of the replacement light fixture 200 and the preexisting light
fixture housing 202 such that airflow is allowed when the replacement
light fixture is installed as a replacement for an air handling light
fixture. In yet another aspect, the reflector assembly can be configured
to overlap the T-grid at the respective ends of the replacement light
fixture 200 only.

[0160]Referring now to FIGS. 43-50, a fifth embodiment of a replacement
light fixture of the present invention is illustrated. In this
embodiment, the base housing 210 comprises a light engine that defines a
pair of longitudinally extending and downwardly facing troughs. As one
will appreciate, each trough is configured to accept one longitudinally
extending light source 12. In another aspect, the pair of troughs is
substantially parallel to each other. In another aspect, the longitudinal
axes of the troughs 227 are spaced a predetermined distance apart. In
another aspect, the troughs are positioned on the opposing edge portions
of the longitudinal edges of the housing.

[0161]In a further aspect, the light engine defines a channel therebetween
the troughs on the top side of the base housing. In one aspect, a ballast
door is configured to allow for hinged access to the channel from the
bottom side of the housing. That is, the ballast door can be readily and
selectively opened from the bottom side of the housing. In this aspect,
the ballast/inverter of the light engine can be mounted onto the top
surface of the channel and access via the opening of the ballast door. It
is also contemplated that the ballast/inverter could be mounted to the
top surface of the ballast door to further simplify access to the ballast
of the light engine and the power source/lines that are positioned above
the housing when it is positioned therein the preexisting light fixture
housing. It is contemplated that a ground strap can be electrically
bonded to the swing down ballast tray.

[0162]One will appreciate that the design of the light engine precludes
having to individually install socket brackets for new lamps. Further,
the light engine design promotes high density stacking. It is
contemplated that a narrow light engine design can be used to allow the
use of T8 lamps with the exemplified replacement light fixture. It is
contemplated that the replacement light fixture can be installed onto a
preexisting SP8 door frame.

[0163]This embodiment of the replacement light fixture further comprises a
pair of brackets and a pair of hinge plates. In one aspect, each bracket
is configured to be mounted to a portion of the longitudinal end walls of
the preexisting light fixture housing. Each bracket defines a mounting
flange that is positioned within the interior of the preexisting light
fixture housing when the bracket is mounted. Further, the bracket is
configured to support or hold itself in place until it can be secured
into position. In operation, the bottom surfaces of the longitudinal ends
of the base housing of the light engine are configured to sit on the
opposed mounting flanges. Thus, the brackets act to support the light
housing until it can be securely fastened. In one exemplary aspect, the
ends of the base housing are connected to the mounting flanges of the
bracket by mechanical means, such as, without limitation, screws, bolts,
self-drilling screws, and the like.

[0164]In another aspect, each hinge plate is configured to be mounted to a
face portion of a bracket. Each hinge plate has a male ridge that extends
the width of the plate such that, when installed onto the bracket, the
male ridge extends inwardly into the interior of the fixture. This
subsequently acts as a light trap for the door assembly of the
replacement light fixture. In one exemplary aspect, the hinge plate is
connected to the bracket by mechanical means, such as, without
limitation, screws, bolts, self-drilling screws, and the like. One
skilled in the art would appreciate that the metallic mechanical means
act to electrically couple the components of the light fixture. In a
further aspect, each hinge plate defines at least one opening that is
configured to complementarily accept a hinge and latching means of the
door assembly of the replacement light fixture.

[0165]The door assembly comprises a metal, such as steel for example,
perimeter frame. Portions of the door assembly form hinge and latching
means, such as, for example hinge bias members, that complementarily and
selectively couple with the hinge and latching means, such as, for
example cam latches. In one aspect, the door assembly comprises a
metallic reflector assembly with snap in polymeric lenses that can be
formed from acrylic for example. In another aspect, the door assemblies
comprising an integrated metallic reflector/light engine with snap in
polymeric lenses. Optionally, a one piece polymeric reflector with
co-molded lenses can be used. In this aspect, it is contemplated that the
lenses can be substantially light transmissive and the reflector portions
can be opaque. In a further aspect, the co-molded lens can include micro
optic patters that negate the need for the use of a diffusing overlay.

[0166]As outlined above, it is contemplated that the reflector and lens
can be, in one example, formed integral to each other or can, in another
example, be separate pieces that can be mounted with respect to each
other and the base housing. In one aspect, the reflector portion of the
reflector assembly is substantially opaque. In another aspect, the
reflectors can have, if desired, a corrugated surface.

[0167]In a further aspect, a reveal can be provided between at least one
edge of the replacement light fixture and the preexisting light fixture
housing such that airflow is allowed when the replacement light fixture
is installed as a replacement for an air handling light fixture. In yet
another aspect, the reflector assembly can be configured to overlap the
T-grid at the respective ends of the replacement light fixture only.

[0168]The preceding description of the invention is provided as an
enabling teaching of the invention in its best, currently known
embodiment. To this end, those skilled in the relevant art will recognize
and appreciate that many changes can be made to the various aspects of
the invention described herein, while still obtaining the beneficial
results of the present invention. It will also be apparent that some of
the desired benefits of the present invention can be obtained by
selecting some of the features of the present invention without utilizing
other features. The corresponding structures, materials, acts, and
equivalents of all means or step plus function elements in the claims
below are intended to include any structure, material, or acts for
performing the functions in combination with other claimed elements as
specifically claimed.

[0169]Accordingly, those who work in the art will recognize that many
modifications and adaptations to the present invention are possible and
can even be desirable in certain circumstances and are a part of the
present invention. Other embodiments of the invention will be apparent to
those skilled in the art from consideration of the specification and
practice of the invention disclosed herein. Thus, the preceding
description is provided as illustrative of the principles of the present
invention and not in limitation thereof. It is intended that the
specification and examples be considered as exemplary only, with a true
scope and spirit of the invention being indicated by the following
claims.